Vehicle convertible roof

ABSTRACT

A convertible roof system for an automotive vehicle includes a roof bow that is operable between extended and retracted positions to vary tension of the roof cover and is actuated by a link that travels along a camming surface when the folding mechanism supporting the cover moves between the raised and stowed position.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] The present invention generally relates to vehicle convertibleroofs, and more particularly to a vehicle convertible roof having a roofbow that is moveable to vary tension of the convertible roof.

[0002] Traditional soft-top convertible roofs for automotive vehiclestypically employ three, four or five roof bows, having an invertedU-shape spanning transversely across the vehicle for supporting a vinyl,canvas or polyester fabric pliable roof cover. A number one roof bow ismounted to a pair of front roof rails and is typically latched to astationary front header panel of the automotive vehicle body disposedabove the front windshield. A number two roof bow is typically mountedto a pair of center roof rails which are pivotally connected to thefront roof rails. Furthermore, a number three, four and any additionaloptional roof bows are commonly mounted to a pair of rear roof railswhich are pivotally coupled to the center roof rails. The roof cover canalso have a hard or rigid portion along with the pliable portion. Forexample, reference should be made to U.S. Pat. No. 5,429,409 entitled“Convertible Top”, which is incorporated by reference herein.

[0003] The roof cover fabrics are exposed to a full range of weatherenvironments and are expected to maintain their original appearance forseveral years. Due to these durability requirements, the roof covers arenormally quite heavy and multi-layered, such as vinyl on cloth or twolayers of cloth with an elastomer interlayer. The technicalspecifications are quite stringent and the fabrics exhibit relativelylittle stretch. However, the roof covers relax substantially in thesunshine or hot environments and shrink in cold environments.

[0004] To compensate for the relaxing and shrinking of the cover, greatcare must be taken when designing the cover and the top stack mechanismof the convertible roof to achieve a taut cover surface without wrinklesregardless of the environmental conditions. Furthermore, care must alsobe taken to achieve such a surface while still permitting easy pull-downand latching (by the driver in the case of a manually operatedconvertible roof). To achieve this balance, first-time closure effortsoften range between 100 to 200 pounds at the factory. After the topstack mechanism remains in the raised position and latched for severaldays, this effort normally drops to about 30 to 50 pounds, which isconsidered acceptable. However, if the top stack mechanism remains inthe stowed position for a period of several days, it may becomedifficult to latch on the first cycle because of the tendency of thecover to return to its nominal unstretched dimensions. Various“stretchable” roof cover fabrics have been tried without success,thereby increasing the incentive to find a means for optimizing abalance between easy latching and taut appearance while utilizing thepresent types of fabrics that are employed in the roof covers.

[0005] The problem of high latching efforts is caused by the varyingtension in the cover material which is acting against the forwardmovement of the number one roof bow to latch to the stationary frontheader panel. Force vector analysis indicated that a pull-down force of20 to 50 pounds at the number one roof bow may be counter balanced witha force of 20 to 50 pounds acting in the plane of the number four roofbow, which yields a force of about 200 pounds in fabric tension of theroof cover. This level of force is adequate for maintaining a tautappearance in a properly fitted roof cover. Thus, if the tension in theroof cover could be limited by making the number four bow adjustable,easy latching can be assured along with a taut appearance.

[0006] In accordance with the present invention, a convertible roofsystem for an automotive vehicle includes a roof bow that is operablebetween extended and retracted positions to vary tension of the roofcover and is actuated by a link that travels along a camming surfacewhen the folding mechanism supporting the cover moves between the raisedand stowed position. In another aspect of the present invention, alatching member is operable to latch an adjustable roof bow in aretracted position and retains the roof bow in the retracted position asthe convertible roof system moves from a stowed position to a raisedposition. In a further aspect of the present invention, a vehicleconvertible roof system with an adjustable roof bow uses a multi-linkassembly that couples the roof bow to a roof rail. The multi-linkassembly includes a first link and a second link that encircles thefirst link and slides along the first link as the adjustable roof bowmoves between extended and retracted positions. In still another aspectof the present invention, a method of operating a convertible roofsystem is disclosed. The method includes latching an adjustable roof bowin the retracted position, maintaining the roof bow in the retractedposition as the convertible top system moves from a stowed position to araised position and tensioning the cover of the convertible top systemby moving the adjustable roof bow to the extended position when thesystem is in the raised position.

[0007] The present invention is advantageous over traditionalconvertible roofs in that the adjustable roof bow enables theconvertible top to have an acceptable pull-down force while alsoproviding adequate tensioning of the roof cover after being latched tothe front windshield header. Furthermore, the present invention isadvantageous because it can use existing roof cover fabrics to providesuch pull-down forces and appearance. The convertible roof of thepresent invention is also advantageous in that the retracting of theadjustable roof bow is performed as part of the movement of theconvertible roof to the stowed position and, as a result, does notrequire complex control schemes or linkage assemblies. Additionaladvantages and features of the present invention will become apparentfrom the following description and appended claims taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

[0009]FIG. 1 is a perspective view of a vehicle with a preferredembodiment of a vehicle convertible roof according to the principles ofthe present invention;

[0010]FIG. 2 is a fragmented side elevation view of the vehicle of FIG.1 with the convertible roof in a raised and latched position and theadjustable roof bow in an extended position and with a camming surfaceaffixed to the vehicle body;

[0011]FIG. 3A is a fragmented side elevation view of the vehicle of FIG.1 with the convertible roof in an intermediate position and theadjustable roof bow in its extended position;

[0012]FIG. 3B is an enlarged fragmented view of a portion of theconvertible roof of FIG. 3A within circle 3B;

[0013]FIG. 4A is a fragmented side elevation view of the vehicle of FIG.1 with the convertible roof in a fully stowed position and theadjustable roof bow in its retracted position;

[0014]FIG. 4B is an enlarged fragmented view of a portion of theconvertible roof of FIG. 4A within circle 4B;

[0015]FIG. 5 is a fragmented side elevation view of the vehicle of FIG.1 with the convertible roof in a fully raised position and theadjustable roof bow in its retracted position;

[0016]FIG. 6 is a fragmented side elevation view of a vehicle with afirst alternate embodiment of a convertible roof according to theprinciples of the present invention with the convertible roof in araised and latched position and an adjustable roof bow in an extendedposition and with a camming surface affixed to the rear roof rail;

[0017]FIG. 7A is a fragmented side elevation view of the vehicle of FIG.6 with the convertible roof in an intermediate position and theadjustable roof bow in its extended position;

[0018]FIG. 7B is an enlarged fragmented view of a portion of theconvertible roof of FIG. 7A within circle 7B;

[0019]FIG. 8A is a fragmented side elevation view of the vehicle of FIG.6 with the convertible roof in the fully stowed position and theadjustable roof bow in its retracted position;

[0020]FIG. 8B is an enlarged fragmented view of a portion of theconvertible roof of FIG. 8A within circle 8B;

[0021]FIG. 9 is a fragmented side elevation view of the vehicle of FIG.6 with the convertible roof in a fully raised position and theadjustable roof bow in its retracted position; and

[0022]FIGS. 10A and B are opposite fragmented side elevation views of aportion of a second alternate embodiment of a convertible roof accordingto the principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] The following description of the preferred embodiment is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

[0024]FIGS. 1-5 show the preferred embodiment of a vehicle convertibleroof 20 according to the principles of the present invention.Convertible roof 20 is employed on an automotive vehicle 22 having apassenger compartment 24 and a boot well or stowage compartment 26.Convertible roof 20 is of the type utilizing a folding or top stackmechanism 28 that partially supports a pliable or flexible roof cover 30and is operable between a fully raised position, as shown in FIGS. 1, 2and 5, and a fully stowed position, as shown in FIG. 4A. Roof cover 30is made from a pliable material, such as vinyl, canvas or a polyesterfabric. A backlite 32 is attached to roof cover 30 and is not pivotallycoupled to top stack mechanism 28. For example, reference should be madeto U.S. Pat. No. 5,887,936 entitled “Backlite System for Use in anAutomotive Vehicle Convertible Roof,” by Cowsert, and U.S. Pat. No.6,102,467 entitled “Backlite Retention System for Use in an AutomotiveVehicle Convertible Roof,” by Laurain et al., both of which are hereinincorporated by reference. Backlite 32 can be made of either a rigidmaterial, such as glass, as shown, or a pliable transparent vinylmaterial (not shown).

[0025] Referring to FIGS. 2-10, convertible roof 20 and top stackmechanism 28 are shown symmetrical along a longitudinal, fore-and-aftcenter line (not shown) of vehicle 22. Top stack mechanism 28 includesright and left roof linkages on the respective right and left sides ofvehicle 22. For brevity, only the left side of top stack mechanism 28 isdiscussed, however, it should be understood that right side linkages arealso provided as part of top stack mechanism 28 and are substantiallymirror images of the left side. Also, when using the terms “fore” and“aft” and “front” and “back” in describing components of convertibleroof 20, such references refer to the orientation of the components whentop stack mechanism 28 is in the fully raised position.

[0026] Top stack mechanism 28 includes a forwardmost or number one roofbow 34, a number two roof bow 36, a number three roof bow 38, and anadjustable or number four roof bow 40 that each extend transverselyacross vehicle 22. Number one roof bow 34 has a front edge that islatched to a stationary front header panel of vehicle 22 disposed abovethe front windshield when in the fully raised position, as shown inFIG. 1. Number one roof bow 34 is fixedly connected to a front roof rail42. Alternatively, number one roof bow 34 can be formed integrally withfront roof rail 42, for example, first roof bow 34 and front roof rail42 can be integrally cast from aluminum or a magnesium alloy.

[0027] Top stack mechanism 28 also includes a center roof rail 44 thatis pivotally connected to front roof rail 42 at pivot 46 and pivotallyconnected to a rear roof rail 48 at pivot 49. Rear roof rail 48 ispivotally connected to a main pivot bracket 50 at pivot 52. Bracket 50is affixed to the body of vehicle 22. One end of a first link 54 ispivotally connected to bracket 50 at pivot 56 while an opposite end offirst link 54 is pivotally connected to center roof rail 44 at pivot 58.One end of a second link 60 is pivotally connected to an end of rearroof rail 48 at pivot 62 while an opposite end of second link 60 ispivotally connected to ends of third and fourth links 64 and 65 at pivot66. The opposite end of third link 64 is pivotally connected to centerroof rail 44 at pivot 68 while an opposite end of fourth link 65 ispivotally connected to front roof rail 42 at pivot 70. Third and fourthlinks 64 and 65 in conjunction with second link 60 control the movementof front roof rail 42 relative to center roof rail 44 when top stackmechanism 28 is moving between the raised and stowed positions. Numbertwo roof bow 36 is pivotally connected to second link 60 at pivot 72.Number three roof bow 38 is pivotally connected to rear roof rail 48 atpivot 74. Number four roof bow 40 is coupled to rear roof rail 48 with amulti-link assembly 76. Multi-link assembly 76 enables number four roofbow 40 to move between an extended position, as shown in FIG. 2, and aretracted position, as shown in FIG. 5, to vary the tension of roofcover 30 when top stack mechanism 28 is in the raised position, asdescribed below.

[0028] Multi-link assembly 76 includes a link or plate 78 that ispivotally connected to an intermediate portion of rear roof rail 48 atpivot 80. An intermediate portion of a crank 82 is pivotally connectedto plate 78 at pivot 84 while an end of crank 82 is pivotally connectedto an end of number four roof bow 40 at pivot 86. Crank 82 is a camfollower that acts like a bell crank. One end of a control link 88 ispivotally connected to plate 78 at pivot 90 while an opposite end ofcontrol link 88 is pivotally connected to an end portion of number fourroof bow 40 at pivot 92 which is between pivot 86 and an intermediateportion of number four roof bow 40. Plate 78, crank 82, number four roofbow 40, and control link 88 form a four-bar linkage defined by pivots84, 86, 92, and 90. This four-bar linkage controls movement of numberfour roof bow 40 relative to plate 78.

[0029] A biasing member 94, in this embodiment in the form of a gasstrut having a fluid compressing piston in a cylinder, is pivotallyattached to plate 78 at pivot 96 and pivotally attached to anintermediate portion of number four roof bow 40 at pivot 98. Biasingmember 94 biases number four roof bow 40 towards its extended positionand resists movement of number four roof bow 40 from its extendedposition toward its retracted position. A stop 100 is located on plate78 and limits movement of plate 78 relative to rear roof rail 48 aboutpivot 80. Stop 100 can take a variety of forms. For example, stop 100can be a threaded bolt that extends through a complementary threadedopening in plate 78. Due to the threadings on stop 100 and in thecomplementary opening in plate 78, stop 100 is adjustable such that theallowed movement of plate 78 relative to rear roof rail 48 about pivot80 can be adjusted by adjusting the length stop 100 extends from plate78 toward rear roof rail 48. A latch 102 is pivotally connected to plate78 at pivot 104 and is operable to lock or latch number four roof bow 40in its retracted position by engaging with a complementary recess 106 onan end portion of number four roof bow 40 between pivots 86 and 92. Abiasing member 108, in this case in the form of a spring, is attached toplate 78 and latch 102. Spring 108 biases latch 102 toward number fourroof bow 40 to enable latch 102 to engage with recess 106 when numberfour roof bow 40 is moved from its extended position to its retractedposition, as described below. Latch 102 is also connected to an actuator109 that is operable to disengage latch 102 from recess 106 to allownumber four roof bow 40 to move from its retracted to its extendedposition as described below.

[0030] Multi-link assembly 76, as stated above, is operable to causenumber four roof bow 40 to move between its extended and retractedpositions. Number four roof bow 40 moves from its extended position toits retracted position as top stack mechanism 28 moves from the raisedposition to the stowed position. During a portion of the movement of topstack mechanism 28 from the raised position to the stowed position oneend of crank 82 will travel along a camming surface 110 which, in thisembodiment, is located on bracket 50. Movement of crank 82 along cammingsurface 110 causes number four roof bow 40 to move from its extendedposition to its retracted position and allows latch 102 to engage withrecess 106 to secure number four roof bow 40 in its retracted position,as described below.

[0031] Referring now to FIGS. 2-5, operation of the preferred embodimentof convertible roof 20 is shown. When it is desired to move convertibleroof 20 from the raised position to the stowed position, the latch (notshown) connecting convertible roof 20 to the front header of vehicle 22is operated to release convertible roof 20 from the front header. Topstack mechanism 28 is then moved manually from the raised position tothe stowed position by moving top stack mechanism 28 in a rearwarddirection. Movement of top stack mechanism 28 rearwardly causes firstlink 54 and rear roof rail 48 to rotate clockwise about respectivepivots 56 and 52. Simultaneously, front roof rail 42 rotates clockwiserelative to center roof rail 44 about pivot 46 and center roof rail 44rotates counterclockwise relative to first link 54 and rear roof rail 48about respective pivots 58 and 49. Also concurrently with the movementof top stack mechanism 28, backlite 32 begins to fall towards stowagecompartment 28 and plate 78 rotates counterclockwise relative to rearroof rail 48 about pivot 80.

[0032] As shown in FIGS. 3A and B, continued movement of top stackmechanism 28 toward the stowed position eventually causes stop 100 onplate 78 to engage with rear roof rail 48. When stop 100 engages withrear roof rail 48, continued rotation of plate 78 counterclockwiserelative to rear roof rail 48 about pivot 80 is prevented. An end ofcrank 82 engages with camming surface 110 on bracket 50 at about thesame time stop 100 engages with rear roof rail 48. With rotation ofbracket 78 about pivot 80 restrained by stop 100 and the engagement ofcrank 82 with camming surface 110, continued movement of top stackmechanism 28 toward the stowed position causes number four roof bow 40to move to its retracted position. Specifically, plate 78 remainssubstantially stationary relative to rear roof rail 48 so that as rearroof rail 48 continues to rotate clockwise about pivot 52, cammingsurface 110 pushes on crank 82 which causes crank 82 to rotate clockwiserelative to plate 78 about pivot 84 which in turn causes control link 88to also rotate clockwise relative to plate 78 about pivot 90 which pullsnumber four roof bow 40 toward its retracted position. Continuedmovement of top stack mechanism 28 toward the stowed position,eventually causes number four roof bow 40 to be retracted a sufficientdistance for latch 102 to engage with recess 106 on number four roof bow40 and lock number four roof bow 40 in its retracted position, as shownin FIGS. 4A and B.

[0033] Top stack mechanism 28 is moved upwardly from the stowed positionand toward the front header of vehicle 22 when it is desired to moveconvertible roof 20 to the raised position. While top stack mechanism 28is moving from the stowed position to the raised position, number fourroof bow 40 remains locked in its retracted position by latch 102. Thus,as shown in FIG. 5, top stack mechanism 28 can be moved to its fullyraised position while number four roof bow 40 remains in its retractedposition and roof cover 30 is relaxed and does not provide a resistingforce to moving top stack mechanism 28 to its fully raised position. Topstack mechanism 28 can then be latched to the front header of vehicle22. Simultaneously with or following the latching of top stack mechanism28 to the top header of vehicle 22, latch 102 is moved away from recess106 by actuator 109 to allow number four roof bow 40 to move from itsretracted position to its extended position under the influence ofbiasing member 94. Number four roof bow 40 then increases the tension ofroof cover 30 to provide a taut appearance to convertible roof 20. Thus,convertible roof 20 can be easily latched in its raised position withoutexperiencing a significant resisting force by tension in roof cover 30.

[0034] Actuator 109 can take a variety of forms. For example, actuator109 can be a cable attached to latch 102 and linked to the latchingmechanism that latches top stack mechanism 28 to front header of vehicle22. When the front header latch is actuated to latch top stack mechanism28 to vehicle 22, the cable can be pulled (by action of the latch) thuspulling latch 102 away from recess 106 and allowing number four roof bow40 to move to its extended position. Alternately, actuator 109 can be asolenoid which is controlled by a microprocessor so that latch 102 ismoved away from recess 106 either simultaneously or subsequent to thelatching of top stack mechanism 28 to the header of vehicle 22 asindicated by an adjacent limit switch. In a different embodiment,actuator 109 can be a manually operated pull cord that moves latch 102and releases number four roof bow 40. Thus, latch 102 can be triggeredor operated in a variety of manners to cause disengagement from recess106 and allow number four roof bow 40 to move from its retractedposition to its extended position.

[0035] Referring now to FIGS. 6-9, a first alternate embodiment of avehicle convertible roof 20 according to the principles of the presentinvention is illustrated and indicated as 20′. Convertible roof 20′ issubstantially identical to convertible roof 20 shown in FIGS. 1-5 with aslightly different multi-link assembly 76′, a different camming surface110′ and a different biasing member 94′. In convertible roof 20′,multi-link assembly 76′ includes a plate 78′ that has a differentconfiguration, does not have a stop and includes a crank 82′ that has adifferent configuration. The configuration of crank 82′ allows it toengage with a camming surface 110′ which, in this embodiment, is on rearroof rail 48. Biasing member 94′ is in the form of a compression springin convertible roof 20′ and performs the same function as biasing member94 in convertible roof 20 discussed above and, as such, will not bedescribed further. Multi-link assembly 76′ performs the same function asmulti-link assembly 76 shown in FIGS. 1-5. That is, multi-link assembly76′ causes number four roof bow 40 to automatically move from itsextended position to its retracted position as top stack mechanism 28moves from the raised position to the stowed position. Multi-linkassembly 76′ also retains number four roof bow 40 in its retractedposition as top stack mechanism 28 moves from the stowed position to theraised position thereby allowing top stack mechanism 28 to be attachedto the front header of vehicle 22 without encountering a significantresistance by roof cover 30.

[0036] In operation, convertible roof 20′ can be moved between theraised position, as shown in FIG. 6, through intermediate positions,such as that shown in FIG. 7A, to a fully stowed position, as shown inFIG. 8A. To move convertible roof 20′ from the raised position to itsstowed position, convertible roof 20′ is unlatched from the front headerof vehicle 22 and is moved rearwardly to cause top stack mechanism 28 tomove toward the stowed position. Movement of top stack mechanism 28toward the stowed position, causes rear roof rail 48 to rotate clockwiseabout pivot 52 which in turn causes plate 78′ of multi-link assembly 76′to rotate counterclockwise relative to rear roof rail 48 about pivot 80.As top stack mechanism 28 is continued to be moved toward the stowedposition, an end of crank 82′ engages with camming surface 110′ on rearroof rail 48. However, because plate 78′ does not include a stop,continued movement of top stack mechanism 28 toward the stowed positiondoes not cause crank 82′ to pull number four roof bow 40 toward theretracted position because not enough force is generated to overcome theforce supplied by biasing member 94′. When top stack mechanism 28 ismoved far enough toward the stowed position, as shown in FIGS. 7A and B,number four roof bow 40 contacts backlite 32 through a portion of roofcover 30. Continued movement of top stack mechanism 28 toward the stowedposition causes backlite 32 to exert a resisting force on number fourroof bow 40 that is translated to plate 78′ and crank 82′. When asufficient resisting force is exerted by backlite 32 on number four roofbow 40, plate 78′ will move counterclockwise relative to rear roof rail48 about pivot 80 which causes crank 82′ to move along camming surface110′, rotate clockwise relative to plate 78′ about pivot 84, and pullnumber four roof bow 40 towards its retracted position. Preferably,multi-link assembly 76′ provides a mechanical advantage sufficient tolimit the required force that backlite 32 exerts on number four roof bow40 to less than about three pounds and preferably less than about twopounds. Continued retraction of top stack mechanism 28 to the fullystowed position eventually causes number four roof bow 40 to beretracted a sufficient distance for latch 102 to engage with recess 106and thereby lock number four roof bow 40 in the retracted position, asshown in FIGS. 8A and B.

[0037] When it is desired to move convertible roof 20′ from the stowedposition to the raised position, top stack mechanism 28 is movedupwardly out of stowage compartment 26 and toward the front header ofvehicle 22. Number four roof bow 40 remains locked in its retractedposition by latch 102 as top stack mechanism 28 moves from the fullystowed position to the fully raised position. Top stack mechanism canthen be latched to the front header of vehicle 22 without encountering asignificant resisting force by roof cover 30. Concurrent with orsubsequent to the latching of top stack mechanism 28 to the front headerof vehicle 22, latch 102 can be triggered to release number four roofbow 40 which will then move to its extended position under the influenceof biasing member 94′ and provides a taut appearance for convertibleroof 20′. Latch 102 can be activated in any of the ways discussed abovewith reference to convertible roof 20. Thus, convertible roof 20′ causesnumber four roof bow 40 to automatically move from an extended positionto a retracted position as convertible roof 20′ is moved from a raisedposition to a stowed position. Convertible roof 20′ can also be movedfrom a stowed position to a raised position while number four roof bow40 remains in its retracted position thereby enabling top stackmechanism 28 to be latched to a front header of vehicle 22 withoutexperiencing resistance from roof cover 30. The tension of roof cover 30can then be adjusted by releasing number four roof bow 40 and allowingit to move to its extended position thereby providing a desired tautappearance for convertible roof 20′.

[0038] Referring to FIGS. 10A and B, a second alternate embodiment oflinkage assembly 76 is shown for use on convertible roof 20′ andindicated as 76″. That is, multi-link assembly 76″ is shown configuredto be used with a top stack mechanism 28 having a camming surface 110″on rear roof rail 48 and number four roof bow 40 experiencing aresisting force from backlite 32 (see FIGS. 7A and B) to cause numberfour roof bow 40 to move from its extended position to its retractedposition. However, it should be understood that multi-link assembly 76″can also be configured to work with convertible roof 20, shown in FIGS.1-5, by altering the configuration of plate 78″, the configuration ofcrank 82″ and adding a stop to plate 78″.

[0039] Multi-link assembly 76″ eliminates control link 88. In place ofthe control link, base plate 78″ is provided with an opening 120 throughwhich an end portion of number four roof bow 40 resides. The end portionof number four roof bow 40 will move or slide through opening 120 asnumber four roof bow 40 moves between its extended and retractedpositions. If desired, opening 120 and/or the end portion of number fourroof bow 40 can be provided with a low friction coating or insert, suchas Teflon, a lubricious engineering grade polymeric fitting or the like,to reduce the friction between opening 120 and the end portion of numberfour roof bow 40. Operation of a convertible roof employing multi-linkassembly 76″ is substantially the same as that shown in FIGS. 6-9 anddiscussed above. Accordingly, operation of a convertible roof employingmulti-link link assembly 76″ is not discussed further.

[0040] It should be appreciated that convertible roof 20 and 20′, whileshown as a manually operated convertible roof, can be a power actuatedconvertible roof without departing from the scope of the presentinvention. That is, a powered actuator, such as a hydraulic cylinder,pneumatic cylinder, electric motor, rotary actuator, or a similarcomponent sufficient to apply an adequate force, can be employed toautomate the movement of the convertible roof between the raised andstowed positions. Such an automatically powered, main actuator for thetop stack mechanism is disclosed in U.S. Pat. No. 5,772,274,incorporated by reference herein. Additionally, while the biasingmembers 94 and 94′ are shown as being either a gas cylinder or a coilspring, it should be appreciated that a mechanical torsion spring orother device such as a bungee cord can be employed. Moreover, it shouldbe appreciated that biasing members 94 and 94′ are designed to provide asubstantially constant amount of tension in roof cover 30 throughout thelife of roof cover 30. The amount of force applied by biasing members 94and 94″ will vary depending upon the fluid pressure and/or spring rateof the biasing members 94 and 94′. The amount of tensioning forceapplied by biasing members 94 and 94′ can be adjusted, if desired bychanging the spring length and/or mounting locations of biasing members94 and 94′ on number four roof bow 40 and/or base plate 78, 78′, 78″.For example, biasing member 94 and 94′ can be provided with a clevis(not shown) on one of its ends and number four roof bow 40 or base plate78, 78′, 78″ can be provided with a plurality of mounting holes throughwhich the clevis can be attached so that the location on number fourroof bow 40 and/or base plate 78, 78′, 78″ can be adjusted to adjust theamount of tensioning force applied by biasing member 94 and 94′.Additionally, it should be appreciated that latch 102 can be other thana hinged pawl as shown. For example, latch 102 can be a sliding bolt ora retracting pin. Furthermore, the releasing of latch 102 from recess106 can be performed by a lanyard, can be mechanically actuated inconjunction with the operation of a front header latching function orindependently of it. It could also be a simple time-delayed gas strutwhich allows a user time to latch the convertible roof to the frontheader prior to the releasing of the roof bow from the retracted to theextended position. Additionally, electrical circuitry in the solenoidswhich are automatically engaged in the proper sequence could be employedwithout deviating from the scope of the present invention. Furthermore,stop 100 can be configured to be non-adjustable, if desired, althoughall the benefits of convertible roof 20 may not be realized. Moreover,camming surfaces 110, 110′, and 110″ can be integral to a component, asshown in FIGS. 6-9, or can be an individual component that is attachedto another component, as shown in FIGS. 1-5 and 10A and B, and can beused with either of the convertible roofs 20 and 20′.

[0041] The description of the invention is merely exemplary in natureand, thus, variations that do not depart from the gist of the inventionare intended to be within the scope of the invention. Such variationsare not to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A convertible roof system for an automotive vehicle, the system comprising: (a) a roof cover; and (b) a linkage assembly supporting at least a portion of said cover, said linkage assembly operable between a raised position and a stowed position, said linkage assembly comprising: (i) a plurality of roof bows, at least a tensioning one of said roof bows being operable between extended and retraced positions to vary tension of said roof cover; and (ii) a latching member operable to latch said tensioning roof bow in said retracted position, said latching member retaining said tensioning roof bow in said retracted position as said mechanism is moved from said stowed position to said raised position.
 2. The system of claim 1, wherein said linkage assembly further comprises a biasing member that biases said tensioning roof bow to said extended position.
 3. The system of claim 1, wherein said latching member engages with a recess on said tensioning roof bow to latch said tensioning roof bow in said retracted position.
 4. The system of claim 1, wherein said linkage assembly further comprises a biasing member that biases said latching member to latch said tensioning roof bow in said retracted position.
 5. The system of claim 1, wherein said latching member is pivotally attached to a link of said linkage assembly.
 6. The system of claim 1, further comprising a camming surface and wherein said linkage assembly further comprises a cam follower that moves along said camming surface during a portion of movement of said linkage assembly between said raised and stowed positions, and said cam follower being operable to cause said tensioning roof bow to move between said extended and retracted positions as said cam follower moves along said camming surface.
 7. The system of claim 1, further comprising an actuator operable to cause said latching member to disengage from retaining said tensioning roof bow.
 8. The system of claim 1, wherein said latching member has a hook-like shape and engages in a recess in a pivotable link to retain said tensioning roof bow.
 9. A vehicle convertible roof system comprising: at least two roof rails coupled together and moving relative to one another between raised and stowed positions; a plurality of roof bows, at least a tensioning one of said roof bows being operable between first and second positions when said roof rails are substantially in said raised position; and a multilink assembly coupling said tensioning roof bow to one of said roof rails, said multilink assembly comprising: (a) a first link; and (b) a second link encircling said first link and operably sliding along said first link as said tensioning roof bow moves between said first and second positions.
 10. The system of claim 9, wherein said first link is a portion of said tensioning roof bow.
 11. The system of claim 10, wherein said portion of said tensioning roof bow is an end portion.
 12. The system of claim 9, further comprising a camming surface and wherein one link of said multilink assembly is a cam follower that moves along said camming surface during a portion of movement of said roof rails between said raised and stowed positions, said cam follower being operable to cause said tensioning roof bow to move between said first and second positions as said cam follower moves along said camming surface.
 13. The system of claim 9, wherein said second link is pivotally connected to one of said roof rails.
 14. The system of claim 9, wherein said first and second positions of said tensioning roof bow correspond respectively to decreasing and increasing tension of said cover when said roof rails are substantially in said raised position, and said tensioning roof bow remains in said first position while said roof rails move from said stowed position to said raised position.
 15. The system of claim 9, wherein said first and second positions of said tensioning roof bow correspond respectively to decreasing and increasing tension of said cover when said roof rails are substantially in said raised position, and said tensioning roof bow moves from said second position to said first position as said roof rails move from said raised position to said stowed position.
 16. A convertible roof comprising a top stack mechanism movable between a raised position and a stowed position, said top stack mechanism comprising a plurality of roof bows, at least a tensioning one of said roof bows being operable between extended and retraced positions to vary roof tension, and a member operably biasing said tensioning roof bow to said extended position.
 17. The roof of claim 16 further comprising a latching member operable to latch said tensioning roof bow in said retracted position, said latching member retaining said tensioning roof bow in said retracted position as said mechanism is moved from said stowed position to said raised position.
 18. The roof of claim 17, wherein said latching member engages with a recess on said tensioning roof bow to latch said tensioning roof bow in said retracted position.
 19. The roof of claim 17, wherein said top stack mechanism includes said latching member and a link, said latching member is pivotally attached to said link.
 20. The roof of claim 16, further comprising a camming surface and a cam follower that moves along said camming surface during a portion of movement of said top stack mechanism between said raised and stowed positions, said cam follower being operable to cause said tensioning roof bow to move between said extended and retracted positions as said cam follower moves along said camming surface.
 21. The roof of claim 16, further comprising a pliable roof cover being tensioned and de-tensioned by said tensioning roof bow.
 22. The roof of claim 16, wherein said tensioning roof bow is a number four bow. 